Specific heat studies of the chiral phase transition in charge ordered 1T-TiSe$_{2}$

ORAL

Abstract

We use high-resolution steady-state ac-micro-calorimetry to investigate the transition of 1T-TiSe$_{2}$ into the charge-ordered state. A mean-field like step of $\sim$ 0.4 J/molK in the specific heat C(T) near 193 K signals the transition into the commensurate CDW state. Upon further cooling, C(T) varies linearly in temperature until near 180 K a clear break in the slope of C(T) by 13mJ/molK$^{2}$ and possibly a small step indicate a second phase transition. Comparisons with theoretical predictions based on the Ginzburg-Landau free energy, with resistivity measurements, and with x-ray diffraction indicate that, at this transition, the commensurate CDW state changes into a helically ordered state along the crystal c-axis.

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Authors

  • Xu Luo

    • Material Science Division, Argonne National Laboratory, Argonne, IL60439

  • J.-P. Castellan

    • Karlsruhe Institute of Technology, D-76021, Karlsruhe, Germany

  • S. Rosenkranz

    • Material Science Division, Argonne National Laboratory, Argonne, IL60439

  • R. Osborn

    • Material Science Division, Argonne National Laboratory, Argonne, IL60439

  • Q. Li

    • Material Science Division, Argonne National Laboratory, Argonne, IL60439

  • G. Karapetrov

    • Department of Physics, Drexel University, Philadelphia, PA 19104

  • J.P.C. Ruff

    • CHESS, Cornell University, Ithaca, NY 14853

  • U. Welp

    • Material Science Division, Argonne National Laboratory, Argonne, IL60439

  • J. Van Wezel

    • H.H. Willis Physics Laboratory, University of Bristol, BS8 1TL, UK